This midcareer investigator award (K24) will provide protected time, resources, and structure that will allow for a progression in my research career trajectory, from a primary focus on HIV prevention, to a more inclusive and extensive conceptualization of prevention in the broader context of sexual and reproductive health (SRH). Further, it will allow me to engage in a comprehensive process of mentorship in the use of mixed methodologies in patient-oriented research. My career development goals are to: 1) expand my knowledge and expertise from HIV prevention alone to a more inclusive focus on sexual and reproductive health, 2) advance an expanded research agenda into the development of effective sexual and reproductive health technologies and interventions, and 3) advance my scholarly role in the use of mixed methods research for health promotion sciences by mentoring fellows and junior investigators in patient oriented research. The proposed mentorship plan will allow me to dedicate the necessary time and effort to fully integrate a comprehensive mixed methods research training program into my mentoring of junior investigators. The proposed research will provide the context for mentoring those investigators. The structured mentorship program will allow me to provide scientific leadership and in-depth methodological training for junior investigators interested in prevention intervention and treatment evaluation research. Through this mentorship in state-of-the-science mixed methods, I will promote the conduct of rigorous health promotion research across a wide range of health promotion sciences. My midcareer development plan will allow me to pursue learning and research activities that broaden my knowledge base and expertise into SRH and help me to better understand user experiences with SRH technologies, and identify those factors that impact use. Critical to use is acceptability. However, current conceptualizations of adherence and acceptability fail to fully articulate and account for patterns of use and non-use. I propose that a new model of use, Effective Use, is required, and propose the conduct of a longitudinal prospective mixed methods study to articulate this model. The concept of Effective Use begins with an inherent demand for the best user experience. It holds that a user's positive experience drives use, and that because use is maintained by this positive experience, higher exposure to the biomedical intervention (e.g., active ingredient), whether for prevention or treatment, is achieved. Relevance to Public Health: Sexual and reproductive health is a global public health priority. Providing efficacious SRH technologies that have the greatest likelihood of use will have the greatest impact on women's health. If successful, an Effective Use model would offer a new paradigm for the development of sexual and reproductive health technologies for women and their partners that will result in increased use and improved sexual and reproductive health outcomes.